avutil/timestamp: remove ""

This may fix an error with C++
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavutil/timestamp.h

@@ -39,7 +39,7 @@
 static inline char *av_ts_make_string(char *buf, int64_t ts)
 {
     if (ts == AV_NOPTS_VALUE) snprintf(buf, AV_TS_MAX_STRING_SIZE, "NOPTS");
-    else                      snprintf(buf, AV_TS_MAX_STRING_SIZE, "%"PRId64"", ts);
+    else                      snprintf(buf, AV_TS_MAX_STRING_SIZE, "%"PRId64, ts);
     return buf;
 }